Recent advances revolutionize treatment of metastatic prostate cancer

Cost-Effectiveness Analysis of Triptorelin, Goserelin, and Leuprolide in the Treatment of Patients With Metastatic Prostate Cancer: A Societal Perspective

OBJECTIVES

Metastatic prostate cancer is the most common malignant cancer and the second leading cause of death due to various types of cancer among men after lung cancer. This study aimed to analyze the cost-effectiveness of triptorelin, goserelin, and leuprolide in the treatment of the patients with metastatic prostate cancer from the societal perspective in Iran in 2020.

METHODS

This is a cost-effectiveness study in which a 20-year Markov transition modeling was applied. In this study, local cost and quality-of-life data of each health state were gathered from cohort of patients. The TreeAge pro 2020 and Microsoft Excel 2016 software were used to simulate cost-effectiveness of each treatment in the long term. The one-way and probabilistic sensitivity analyses were also performed to measure robustness of the model outputs.

RESULTS

The findings indicated that the mean costs and utility gained over a 20-year horizon for goserelin, triptorelin, and leuprolide treatments were $ 13 539.13 and 6.365 quality-adjusted life-years (QALY), $ 18 124.75 and 6.658 QALY, and $ 26 006.92 and 6.856 QALY, respectively. Goserelin was considered as a superior treatment option, given the estimated incremental cost-effectiveness ratio. The one-way and probabilistic sensitivity analyses confirmed the robustness of the study outcomes.

CONCLUSIONS

According to the results of the present study, goserelin was the most effective and cost-effective strategy versus 2 other options. It could be recommended to policy makers of the Iran healthcare system to prioritize it in clinical guidelines and reimbursement policies.

Treatment Combinations with DNA Vaccines for the Treatment of Metastatic Castration-Resistant Prostate Cancer (mCRPC)

Simple Summary

The only vaccine approved by FDA as a treatment for cancer is sipuleucel-T, a therapy for patients with metastatic castration-resistant prostate cancer (mCRPC). Most investigators studying anti-tumor vaccines believe they will be most effective as parts of combination therapies, rather than used alone. Unfortunately, the cost and complexity of sipuleucel-T makes it difficult to feasibly be used in combination with many other agents. In this review article we discuss the use of DNA vaccines as a simpler vaccine approach that has demonstrated efficacy in several animal species. We discuss the use of DNA vaccines in combination with traditional treatments for mCRPC, and other immune-modulating treatments, in preclinical and early clinical trials for patients with mCRPC.

Abstract

Metastatic castration-resistant prostate cancer (mCRPC) is a challenging disease to treat, with poor outcomes for patients. One antitumor vaccine, sipuleucel-T, has been approved as a treatment for mCRPC. DNA vaccines are another form of immunotherapy under investigation. DNA immunizations elicit antigen-specific T cells that cause tumor cell lysis, which should translate to meaningful clinical responses. They are easily amenable to design alterations, scalable for large-scale manufacturing, and thermo-stable for easy transport and distribution. Hence, they offer advantages over other vaccine formulations. However, clinical trials with DNA vaccines as a monotherapy have shown only modest clinical effects against tumors. Standard therapies for CRPC including androgen-targeted therapies, radiation therapy and chemotherapy all have immunomodulatory effects, which combined with immunotherapies such as DNA vaccines, could potentially improve treatment. In addition, many investigational drugs are being developed which can augment antitumor immunity, and together with DNA vaccines can further enhance antitumor responses in preclinical models. We reviewed the literature available prior to July 2020 exploring the use of DNA vaccines in the treatment of prostate cancer. We also examined various approved and experimental therapies that could be combined with DNA vaccines to potentially improve their antitumor efficacy as treatments for mCRPC.

High Mobility Group Box-1 (HMGB1): A Potential Target in Therapeutics

High mobility group box-1 (HMGB1) mainly belongs to the non-histone DNA-binding protein. It has been studied as a nuclear protein that is present in eukaryotic cells. From the HMG family, HMGB1 protein has been focused particularly for its pivotal role in several pathologies. HMGB-1 is considered as an essential facilitator in diseases such as sepsis, collagen disease, atherosclerosis, cancers, arthritis, acute lung injury, epilepsy, myocardial infarction, and local and systemic inflammation. Modulation of HMGB1 levels in the human body provides a way in the management of these diseases. Various strategies, such as HMGB1-receptor antagonists, inhibitors of its signalling pathway, antibodies, RNA inhibitors, vagus nerve stimulation etc. have been used to inhibit expression, release or activity of HMGB1. This review encompasses the role of HMGB1 in various pathologies and discusses its therapeutic potential in these pathologies.

Downregulation of Collagen COL4A6 Is Associated with Prostate Cancer Progression and Metastasis

Aims: To determine the association between collagen type IV alpha 6 (COL4A6) expression levels and prostate cancer invasion and metastasis. Methods: We analyzed three Gene Expression Omnibus (GEO) datasets through the GEO2R online tool to obtain the set of differentially expressed genes (DEGs) between malignant and nonmalignant prostate tissues, and further analyzed the COL4A6 gene's expression in databases. Western blot assays, real-time quantitative polymerase chain reaction analysis, and immunofluorescence staining were used to detect COL4A6 gene expression. Wound healing assays and cell invasion transwell assays were performed to measure cell invasion and siRNA was used to knock down COL4A6 gene expression. Results: Through the use of bioinformatic tools we showed that the COL4A6 gene is one of the highly downregulated genes in prostate cancer; additionally, hypermethylation of the COL4A6 promoter in prostate cancer is correlated with lower expression levels. We also showed that downregulation of COL4A6, which activates the p-FAK/MMP-9 signaling pathway in prostate cancer cells, is associated with prostate cancer cell metastasis based on data retrieved from The Cancer Genome Atlas (TCGA) and GEO databases. Finally, we found that the COL4A6 protein is localized extracellularly and its expression is positively correlated with disease-free survival of prostate cancer patients. Conclusion: Our results indicate that downregulation of COL4A6 may promote prostate cancer progression and invasion. Additionally, COL4A6 and its promoter methylation status could be valuable markers for prostate cancer prognoses.

KLF5 inhibits STAT3 activity and tumor metastasis in prostate cancer by suppressing IGF1 transcription cooperatively with HDAC1

KLF5 is frequently deleted and downregulated in prostate cancer, and recently it has been reported that KLF5 loss is enriched in the aggressive branches of prostate cancer evolution. However, why KLF5 loss is associated with prostate cancer aggressiveness is still not clear. Herein, we analyzed KLF5 expression in TCGA and GEO database, as well as prostate cancer tissue microarray, and found that KLF5 expression significantly decreased in prostate cancer accompanying with tumor progression; moreover, KLF5 downregulation was associated with shorter survival of patients. Interestingly, we also found that KLF5 expression was obviously lower in prostate cancer metastases than in localized tissues, indicating that KLF5 downregulation is associated with prostate cancer invasion and metastasis. To assess this effect of KLF5, we knocked down KLF5 in prostate cancer cells and found that KLF5 knockdown promoted invasive ability of prostate cancer cells in vitro and in vivo. Moreover, we found that KLF5 downregulation enhanced the expression of IGF1 and STAT3 phosphorylation, while block of IGF1 with antibody decreased the enhancement of STAT3 activity and prostate cancer cell invasive ability by KLF5 knockdown, indicating that KLF5 inhibits prostate cancer invasion through suppressing IGF1/STAT3 pathway. Mechanistically, we found that KLF5 interacted with deacetylase HDAC1 and KLF5 is necessary for the binding of HDAC1 on IGF1 promoter to suppress IGF1 transcription. Taken together, our results indicate that KLF5 could be an important suppressor of prostate cancer invasion and metastasis, because KLF5 could suppress the transcription of IGF1, a tumor cell autocrine cytokine, and its downstream cell signaling to inhibit cell invasive ability, and reveal a novel mechanism for STAT3 activation in prostate cancer. These findings may provide evidence for the precision medicine in prostate cancer.

Long noncoding RNA DANCR promotes invasion of prostate cancer through epigenetically silencing expression of TIMP2/3

LncRNA DANCR suppresses differentiation of epithelial cells, however, its function in prostate cancer development is still unknown. In the present study, we found the expression of DANCR increases in prostate cancer tissues and cells compared to normal prostate tissues and cells, moreover, DANCR promotes invasion and migration of prostate cancer cells in vitro and metastasis of tumor xenografts in nude mice. Mechanistically, we found that TIMP2/3, which are critical metastasis inhibitor of prostate cancer, were down-regulated by DANCR synergistically with EZH2 through epigenetically silencing their promoter by chromatin immunoprecipitation assay. In addition, we further investigated whether DANCR is regulated by the differentiation-promoting androgen-androgen receptor (AR) pathway and found that DANCR expression is repressed by androgen-AR; furthermore, DANCR impedes the upregulation of TIMP2/3 and the suppression of invasion and migration by androgen-AR. On the other hand, interestingly, we found that in prostate cancer cells DANCR knockdown decreased the promotion of invasion and migration by the treatment of enzalutamide, which is an AR inhibitor. In summary, our results indicate that DANCR promotes prostate cancer invasion and metastasis through repressing the expression of TIMP2/3, and suggest that DANCR could be a potential target for preventing prostate cancer metastasis, and knockdown DANCR may lessen the potential side effect of AR inhibitor.

HMGB1-mediated autophagy confers resistance to gemcitabine in hormone-independent prostate cancer cells

As a main treatment of prostate cancer, castration therapy has been widely applied in the clinic. However, the therapeutic strategy for hormone-independent prostate cancer (HIPC) was not satisfied. Gemcitabine is an important chemotherapeutic agent that has been approved for the treatment of numerous human solid tumors, including HIPC, whereas the gemcitabine resistance has become a serious problem in clinical chemotherapy. In the present study, the mechanisms of resistance to gemcitabine were investigated in HIPC cell lines. The results demonstrated that the autophagy markers were induced significantly in HIPC cells subsequent to gemcitabine treatment. Meanwhile, administration of gemcitabine to HIPC cells increased the expression of high mobility group box1 (HMGB1). Furthermore, the gemcitabine-induced autophagy response was attenuated in stable HIPC cells harboring HMGB1 shRNA. Notably, the HIPC cells stably transfected with HMGB1 shRNA or treated with autophagy inhibitors were more sensitive to gemcitabine compared with the control group. These data suggested that inhibition of HMGB1 increased the sensitivity to gemcitabine by decreasing autophagy response in HIPC cells. Overall, the present findings demonstrate a new mechanism for the resistance to gemcitabine in HIPC cell lines.

microRNA-802 inhibits epithelial-mesenchymal transition through targeting flotillin-2 in human prostate cancer

miRNAs are a class of non-coding RNAs that exert critical roles in various biological processes. The aim of the present study was to identify the functional roles of miR-802 in regulating epithelial-mesenchymal transition (EMT) in prostate cancer (PCa). miR-802 expression was detected in 73 pairs of PCa samples and PCa cell lines (PC3 and DU145 cells) by qRT-PCR. Cell proliferation was detected using MTT assay, and cell apoptosis was evaluated using flow cytometry. Transwell assay was conducted to investigate cell migration and invasion. Expression analysis of a set of EMT markers was performed to explore whether miR-802 is involved in EMT program. Xenograft model was established to investigate the function of miR-802 in carcinogenesis in vivo The direct regulation of Flotillin-2 (Flot2) by miR-802 was identified using luciferase reporter assay. miR-802 was remarkably down-regulated in PCa tissues and cell lines. Gain-of-function trails showed that miR-802 serves as an 'oncosuppressor' in PCa through inhibiting cell proliferation and promoting cell apoptosis in vitro Overexpression of miR-802 significantly suppressed in vivo PCa tumor growth. Luciferase reporter analysis identified Flot2 as a direct target of miR-802 in PCa cells. Overexpressed miR-802 significantly suppressed EMT, migration and invasion in PCa cells by regulating Flot2. We identified miR-802 as a novel tumor suppressor in PCa progression and elucidated a novel mechanism of the miR-802/Flot2 axis in the regulation of EMT, which may be a potential therapeutic target.

High Levels of Medical Mistrust Are Associated With Low Quality of Life Among Black and White Men With Prostate Cancer

BACKGROUND

Medical mistrust is thought to affect health care-based decisions and has been linked to poor health outcomes. The effects of medical mistrust among men with prostate cancer are unknown. Thus, the goal of the current study is to examine the association between medical mistrust and quality of life (QOL) among black and white men with prostate cancer.

METHODS

A total of 877 men (415 black, 462 white) with prostate cancer between the ages of 40 to 81 years who entered the North Carolina Central Cancer Registry during the years 2007 and 2008 were retrospectively recruited. The dependent variable was overall QOL measured by the Functional Assessment of Cancer Therapy-Prostate questionnaire. The primary independent variable was medical mistrust. Multivariate regression analysis was used to assess the association between medical mistrust and overall QOL.

RESULTS

Compared with white men, black men reported a higher level of medical mistrust (black = 2.7, white = 2.4; P < .001) and lower QOL (black = 134.4, white = 139.5; P < 0.001). After controlling for demographical and clinical variables, higher levels of medical mistrust were associated with a reduction in overall QOL among men with prostate cancer (beta = -7.73; standard error = 1.54) CONCLUSIONS: Higher levels of medical mistrust are associated with reduced overall QOL among black and white men with prostate cancer. Interventions targeted to reduce medical mistrust may be effective in increasing the overall QOL of men with prostate cancer.

Prostate cancer vaccines in combination with additional treatment modalities

Immunotherapy has been investigated in both preclinical studies and clinical trials as a new therapy for prostate cancer. Vaccines, including those that utilize dendritic cells, viruses, or DNA, immunize against prostate-specific antigen and prostatic acid phosphatase. The vaccines have long been studied as monotherapy for the cancer, but increasingly more trials have been initiated in combination with other modalities. These include radiation, chemotherapy, and androgen deprivation therapy. This review describes and discusses the various combinations of vaccine immunotherapies.

Cancer survivors' perspectives and experience on western medicine and traditional Chinese medicine treatment and rehabilitation: a qualitative study

BACKGROUND

In the People's Republic of China, both western medicine (WM) and traditional Chinese medicine (TCM) are the main treatment and rehabilitation options for cancer patients. This study aimed to explore cancer survivors' perspectives and experience of treatment and rehabilitation, in order to promote patient-centered activities of treatment and rehabilitation.

METHODS

Using a qualitative research approach, 68 cancer survivors were recruited from eight community cancer rehabilitation organizations in Shanghai, People's Republic of China. Eight focus group interviews were conducted. All these interviews were transcribed verbatim, and the data were analyzed by theme analysis.

RESULTS

WM was the main choice in treatment phase though study participants noted more side effects. TCM was primarily used in the recovery phase. The lack of communication between doctors and cancer patients appears to affect treatment adherence and impair the doctor-patient relationship. WM was expensive for diagnostic procedures and treatment, while the cumulative costs of frequent use of TCM in the long rehabilitation period were also high. Both treatment options created significant perceived economic burden on patients. Conflicting information about dietary supplements tended to make cancer survivors confused.

CONCLUSION

Improving the communication between doctors and cancer patients helps to ameliorate cancer patient adherence and the effect of treatments. It is essential to educate cancer patients about the effect and cost of both WM and traditional TCM. Meanwhile, marketing management and guidance to consumers regarding use of dietary supplements in the cancer rehabilitation field are also necessary.

Radium 223 dichloride: a multidisciplinary approach to metastatic castration-resistant prostate cancer

ABSTRACT 

The role of nuclear medicine physicians in the multidisciplinary team for the management of patients with prostate cancer has been restricted because of a lack of available tools. The only drugs approved to relieve pain related to bone metastases were β-emitting radiopharmaceuticals. These drugs did not prove to prolong survival when used as single agent and resulted associated with important adverse events. This situation has changed with the introduction of radium 223 because of evidence of improved survival in patients, the good safety profile and the opportunity to avoid clonal selection of tumor cells. Cooperation among physicians involved in cancer management will lead to improvements in the treatment of bone metastases due to prostate cancer and is thought to extend to other tumor types.

Exploiting synergy: immune-based combinations in the treatment of prostate cancer

Cancer treatment is being revolutionized by the emergence of immunotherapies such as immune checkpoint inhibitors and therapeutic cancer vaccines. Prostate cancer is amenable to such therapeutic approaches. The improved understanding of the relationship between the immune system and tumors has allowed therapeutic targeting of immune checkpoints and tumor associated antigens to be developed. Furthermore, interventions used in prostate cancer are capable of impacting the immune system. As demonstrated by preclinical data and emerging clinical data, radiation therapy, anti-androgen therapy, and chemotherapy can be used with immunotherapies to obtain synergistic results. Current and future clinical trials will further investigate these principles as immunotherapeutics are combined with each other and standard therapies for optimal clinical utility.

Positive nin one binding protein expression predicts poor outcome in prostate cancer

Nin one binding protein (NOB) 1 has been reported to be involved in cancer. However, the role of NOB1 in prostate cancer (PCa) has yet to be elucidated. The present study aimed to investigate the clinical role of NOB1 in PCa. The gene and protein expression levels of NOB1 were detected using quantitative polymerase chain reaction and western blot analysis in fresh samples of PCa and matched adjacent noncancerous tissues (n=32). NOB1 expression was also assessed using immunohistochemistry in a large number of patients with PCa (n=456) and paired adjacent noncancerous tissues between December 2003 and December 2010. The association between NOB1 expression and clinicopathological features and prognosis was investigated. The expression of NOB1 was found to be higher in the fresh samples of PCa than in the paired adjacent noncancerous tissues at the gene and protein levels. Immunohistochemistry revealed that the positive expression rates of NOB1 in PCa and the paired adjacent noncancerous tissues were 53% (242/456) and 6.1% (28/456), respectively. NOB1 expression was significantly correlated with Gleason score (P<0.001) and distant metastasis (P<0.001). Furthermore, patients with PCa with positive NOB1 expression had lower overall survival and recurrence‑free survival (RFS) compared with those with negative NOB1 expression. Multivariate analysis showed that NOB1 was an independent marker of RFS (hazard ratio, 3.45; 95% confidence interval, 1.41‑6.35; P=0.006). These findings suggest that NOB1 may be a potential prognostic indicator for PCa.

Recent advances in bone-targeted therapies of metastatic prostate cancer

Prostate cancer is one of the most common malignancies affecting men worldwide, with bone being the most common site of metastasis in patients that progress beyond organ confinement. Bone metastases are virtually incurable and result in significant disease morbidity and mortality. Bone provides a unique microenvironment whose local interactions with tumor cells offer novel targets for therapeutic interventions. Several attractive molecules or pathways have been identified as new potential therapeutic targets for bone metastases caused by metastatic castration-resistant prostate cancer. In this review, we present the recent advances in molecular targeted therapies for prostate cancer bone metastasis focusing on therapies that target the bone cells and the bone microenvironment. The therapies covered in this review include agents that inhibit bone resorption, agents that stimulate bone formation, and agents that target the bone matrix. Suggestions to devise more effective molecular targeted therapies are proposed. Hopefully, with better understanding of the biology of the disease and the development of more robust targeted therapies, the survival and quality of life of the affected individuals could be significantly improved.